ORNL 3-D printer in use. Image: ORNLResearchers at the U.S. Dept. of Energy (DOE)’s Oak Ridge National Laboratory (ORNL) are working with aircraft makers to determine energy savings through the use of additive manufacturing, also known as 3-D printing.

Sachin Nimbalkar and his ORNL colleagues are printing airplane parts to show additive manufacturing’s potential as a technology that should be considered foundational to processes seeking more energy efficiency.

Additive manufacturing builds products precisely, layer-by-layer, and is distinctly different from traditional subtractive manufacturing processes, which take raw material and cut it down into a desired shape and size.

“All the data on how much energy is being consumed by traditional subtractive processes is available,” Nimbalkar said, “so it is vital we have a consistent methodology to calculate lifecycle energy consumption and savings in additive manufacturing projects.”

Nimbalkar is helping to develop two analytical tools to do just that. The Excel-based tools are providing the methodology to calculate the energy consumed in both the conventional method and the additive manufacturing method, illustrating how much energy the switch to 3-D printing saves.

ORNL analysts are using data from an aircraft manufacturer to determine additive manufacturing’s energy savings. The manufacturer is targeting less critical components such as cabin brackets, in all about 120 different bracket types.

“Airplanes contain a lot of brackets. Some of the more basic technical cabin systems have more than 250,000 installed,” Nimbalkar said. By optimizing the bracket design in computer-aided design (CAD) software and building them from titanium powders instead of titanium ingots, the manufacturer saved 1.56 pounds per bracket.

That’s a 50 to 80% mass savings, knocking the average weight of the conventional bracket from 2.4 pounds down to less than a pound.

“What is really important, though, is comparing the manufacturing processes on their lifecycle frameworks,” Nimbalkar said. “Even though additive manufacturing saves a lot of energy and money in the long run, some of its processes are energy intensive.”

Most products go through five different lifecycle phases: material, manufacturing, freight and distribution, use and disposal. Although additive manufacturing may consume more energy in one or two phases, it almost always saves energy and reduces emissions overall.

“Reducing a plane’s weight saves fuel,” Nimbalkar said. “By using a blended conversion factor, we can take into account the saved jet fuel from the reduced plane weight, the saved coal and electricity used during manufacturing and the saved gasoline from lighter freight and distribution and use our tools to calculate the reduced carbon dioxide emissions.”

In total, additive manufacturing amounts to 4,141 metric tons of reduced carbon dioxide emissions per plane over the plane’s 30 year lifespan.

In the past, when researchers calculated and provided the impacts and benefits of their proposed projects, they focused on only one or two phases. Now, however, they realize all phases are important and need to be researched together.

Source: Oak Ridge National Laboratory